JP2020521636A - Control method of hot-rotating shape/characteristic integration of tubular member based on hot working diagram - Google Patents

Abstract

The present invention discloses a method of controlling the shape/characteristic integration of the hot rolling of the cylindrical member based on the hot working diagram, and the dynamic recrystallization temperature and strain rate generated in the thermoplastic forming process of the metal material which is difficult to deform. Perform high temperature mechanical performance test of metallic materials within the range. Based on the criteria of power loss and current instability in the thermoplastic molding process, the relationship between current stress and strain was obtained in the performance test of high temperature mechanics, and the power loss diagram and current instability diagram at different strains were constructed. To do. Combine the power loss diagram and the current instability diagram to obtain the hot working diagram of the material. Based on the distribution of the power loss rate coefficient η and the judgment of the current instability, the heat of the power loss rate coefficient η under the conditions of potentially dangerous molding conditions and safe molding conditions of the current flow instability criterion is satisfied. A molding condition advantageous for plastic molding is analyzed and obtained. Finally, the material obtained according to the hot working diagram is advantageous in the temperature and strain rate of hot forming, and is subjected to hot strong rotational forming of tubular members. [Selection diagram] Figure 8

Description

The present invention relates to hot working drawings and belongs to the field of hot forming of metallic materials. In particular, the present invention relates to a method for controlling the shape/characteristic integrated hot rolling of a tubular member according to a hot working diagram.

It is the characteristics and development tendency of the current plastic forming technology that the conventional plastic forming has realized the excellent structural performance of the formed part in addition to the requirement for dimensional accuracy. Along with the development of highly precise technology for airplanes, spacecrafts, Defense Forces, ships, etc., its application to tubular members having high dimensional accuracy and good high-temperature performance is becoming more and more widespread. However, such alloys have large deformation resistance at room temperature and poor plasticity, and it is extremely difficult to perform plastic forming at room temperature. Strong hot-rolling hot forming, which has the characteristic of point-load continuous partial forming, is currently one of the most effective methods for obtaining such a metal tube member that is difficult to deform. In the hot strong rotation process, the forming mechanism is complicated by the coupling action of heat, and how to control the combination of forming temperature and each process parameter is to control the cylindrical member with high dimensional accuracy and high temperature performance at the same time. It's the key to getting it.

Besides material chemical composition, microstructure morphology is a determinant of material performance. Therefore, the microstructure change is the key to determine the product performance in the process of strong hot rolling. In order to study the change mechanism of the microstructure in the process of high-speed hot-rolling, the conventional method is to use the texture phase microscope (OM), X-ray diffraction (XRD), backscattering electron diffraction (EBSD), etc. To study experimentally. However, due to the limitation of experimental means, it is not possible to realize dynamic observation of microstructure, it is difficult to predict and control by experience, there is a certain blindness, and it takes time and labor.

Shape/property integrated control is an important development direction of plastic forming technology. In rotary press molding, mainly research on optimization of macroscopic molding quality and process parameters for rotary press defect control is currently attracting attention, and research on microscopic microstructural change mechanism is also adopted the above experimental method. Therefore, it is only necessary to analyze the microscopic structure after molding, and there is no need to study macroscopic molding quality and microscopic structural changes in a coordinated manner. A shape/characteristic integrated control method is not provided either.

The object of the present invention is to overcome the above-mentioned drawbacks and deficiencies of the prior art, to provide a control method of hot-rolling shape/property integration of a tubular member based on hot-working drawings, and to perform blind experiments and materials Is to avoid waste and take full advantage of the material's performance potential. The technical solution of the present invention considers both the macroscopic flow of the material during processing and the microstructure change during deformation of the material, and simultaneously obtains a tubular member with high dimensional accuracy and good tissue performance. be able to.

The control method for the hot strong rotation shape/characteristic integration of the cylindrical member based on the hot working diagram is
High temperature mechanics of metal materials under the conditions of temperature, strain rate and strain at which dynamic recrystallization occurs, based on the difference of dynamic recrystallization temperature, strain rate and strain occurring during thermoplastic forming process of different metal materials Step (1) of performing a performance test,
A step (2) of performing an interpolation calculation on the relation between the flow stress and the strain obtained under the limited test temperature and strain rate sample points;
Based on the criteria of power loss and current instability in the thermoplastic forming process, the relationship between current stress and strain was obtained in the extended high temperature dynamics performance test, and the power loss diagram and current non-current at different strains were obtained. Step (3) of constructing the stability diagram,
Combine the power loss diagram and the current instability diagram to obtain the hot working diagram of the material. Based on the distribution of the power loss factor η and the judgment of the current instability, the heat of the power loss factor η under the conditions of potentially dangerous molding conditions and safe molding conditions Analyzing and obtaining molding conditions advantageous for plastic molding;
Finally, the material obtained according to the hot working diagram is advantageous for the temperature and strain rate of hot forming, and the hot strong rotational forming process parameters are established, and the tubular member is subjected to hot strong rotational forming to obtain the dimensional accuracy. And (5) obtaining a tubular member satisfying the requirements for tissue performance.

The metal material of the step (1) is a metal or metal alloy having a middle-to-low layer defect in which dynamic recrystallization is likely to occur in the thermoplastic molding process, and the high temperature mechanical performance test temperature of the step (1) is the dynamic of the material. It is within the range of 50° C. below the recrystallization temperature and 50° C. above the thermoplastic molding temperature.

The hot working drawing of the step (5) is a hot working drawing based on the dynamic material model.

The strain rate of the high temperature mechanical performance test in the step (1) is in the range of 0.01/s to 10/s according to the distribution of the strong rotational strain rate of the tubular member. The high temperature mechanical performance test of step (1) ensures that the strain amount is 0.6 or more.

The interpolation calculation of step (2) above expands the temperature and strain rate test sample numbers.

The strain rate sensitivity coefficient m in the above-mentioned criterion of instability of current transformation in the step (3) is the strain rate of the current stress σ.
, Which determines the distribution of energy G lost by plastic deformation and energy J lost by microstructural changes,
The amount of work that the external force exerts on the unit volume material in a unit time in the material processing process is P, that is, the total energy obtained by the material is the stress σ and the strain rate.
Which is converted into the energy G consumed by the plastic deformation of the material and the energy J consumed by the microstructural change.
The ideal energy loss system is considered to be equal to the energy consumed by plastic deformation and microstructural change, but usually the material is in a non-linear energy loss state, and the Strain rate of stress σ
, The strain rate sensitivity coefficient m describes its distribution ratio.

The dangerous forming condition of the step (4) is a condition satisfying the current instability criterion based on the irreversible thermodynamic extreme value principle of large plastic deformation explained by the strain rate sensitivity coefficient m,
Based on the irreversible thermodynamic extremum principle of large plastic deformation, the current instability criterion is constructed using the function of velocity sensitivity coefficient m and strain rate.
An advantageous condition for thermoplastic molding is a large molding condition that explains the power loss rate coefficient η occupied by the energy J lost due to the change in microstructure. When placed in an ideal linear energy loss system, the energy lost from the microstructure is the largest J _max =P/2, and therefore, based on the relationship between the total energy P obtained from the material and the loss energy, the strain The function of the speed sensitivity coefficient m is used to explain the power loss rate η, and thus the proportion of the energy J lost from the microstructure.

It is necessary to control the hot strong rotational molding temperature in the step (5) within a range of ±25° C., which is advantageous to the thermoplastic molding temperature obtained from the hot molding diagram.

The hot strong rotational forming strain rate in the step (5) is realized by controlling the rotating wheel forming angle, the rotating wheel feed ratio, the spindle rotation, the thinning rate and/or the blank wall thickness,
The hot hot rotary forming process parameters are determined by the strain rate of the strong rotary press deformation region of the tubular member.
And the rotary wheel forming angle α _ρ , the blank wall thickness t ₀ before the rotary press, the wall thickness t _f of the workpiece after the rotary press, the wall thickness thinning ratio φ _t , and the feed speed v ₀ .
Where α _ρ is the rotary wheel forming angle, t ₀ is the blank wall thickness before rotary pressing, t _f is the workpiece wall thickness after rotary pressing, and t _θf is the blank outer surface before rotary pressing. And the distance from the different θ layers between the outer surfaces of the workpiece after rotary pressing to the inner surface of the workpiece. φ _t is the wall thickness thinning ratio, v ₀ is the flow velocity of the molding region mass point in front of the rotating wheel (relative to the rotating wheel), and in reverse rotational molding, v ₀ is equal to the feed rate and its feed ratio f The relationship with the spindle rotation n is v ₀ =f·n.

The dynamic recrystallization conditions of the step (1) are as follows, and in the middle-low layer defect metal material described in the step (1), when the dislocation density reaches a critical value in the thermoplastic molding process, the crystal grains are This structure change process is called dynamic recrystallization because it forms recrystallized nuclei with extremely low dislocation density and easily grows at the boundaries and stress concentration points with high dislocation density, and distinguishes recrystallization during the heat treatment process. ..

The determination of the dynamic recrystallization temperature and the strain rate of a metallic material is mainly influenced by various factors such as the material's structural state, chemical composition, and molding morphology. Regarding the strain rate, a normal forming method is considered, and in the present invention, hot hot rotation forming is performed. The strain rate is usually in the range of 0.01/s to 10/s, and the dynamic recrystallization temperature at different strain rates can refer to the recrystallization temperature during heat treatment, but Is mainly obtained by testing.

1. The technical solution adopted by the present invention can realize the control of the hot strong rotary forming rotary shape/characteristic integration from the physical mechanism level.
2. The technical solution adopted by the present invention can simultaneously obtain a tubular member having high dimensional accuracy and good tissue performance.
3. The technical solution adopted by the present invention makes it possible to obtain dangerous molding conditions for thermoplastic molding of metal materials, and avoid molding defects and reduction.
As described above, the present invention not only has a highly accurate external dimension for a metal thin-walled tubular component that is difficult to deform, but also has a finer and more uniform micro-grain structure that is free from the phenomenon of instability in current flow. In this way, it is possible to realize integrated control of dimensional accuracy and tissue performance of a metal tubular part that has good mechanical performance and is difficult to deform.

6 is a calculation formula of a strain rate of a strong rotary press deformation region of a tubular member. It is the composition of energy in the thermoplastic molding process. It is a strain rate sensitivity coefficient formula. Ideally linear and non-linear energy loss distribution. It is a power loss rate coefficient formula. It is a criterion for instability of current change based on the irreversible thermodynamic extreme value principle of large plastic deformation. It is a flow chart of an example of the present invention. It is a schematic diagram of a cylindrical member obtained by strong hot rotation of the present invention. It is a sample figure of the high temperature plane strain compression test of the present invention. FIG. 3 is a load schematic diagram of the high temperature plane strain compression test of the present invention. It is a heat load curve figure of the high temperature mechanical performance test of this invention. It is a calculation formula of high temperature plane strain compressive current stress strain of the present invention. It is the relationship of the change current stress strain obtained by the high temperature plane strain compression of the present invention. It is a power loss diagram obtained by the present invention. FIG. 4 is a current instability diagram obtained by the present invention. It is a model hot work drawing based on the dynamic material obtained by the present invention. FIG. 3 is a hot work diagram and a metal phase when the Haynes 230 nickel-based high temperature alloy strain of the present invention is 1. FIG. Among them, FIG. 17a is a hot work diagram when the Haynes 230 nickel base high temperature alloy strain of the present invention is 1. FIG. 17b is one of the metal phases of the Haync230 nickel-based high temperature alloy of the present invention when the strain is 1. FIG. 17c is the second of the metallic phases when the strain of Haync230 nickel-based high temperature alloy of the present invention is 1. FIG. 17d is three of the metallic phases when the strain of Haync230 nickel-based high temperature alloy of the present invention is 1. It is a schematic diagram of a hot strong rotation forming cylindrical member blank of the present invention. It is a rotary press molding schematic of the reverse rotation pitch of the three-rotation wheel of this invention. It is a Haync230 nickel-based high temperature alloy hot rolling strong metallurgical structure of the present invention. It is a high temperature uniaxial tension sample figure of this invention.

Hereinafter, the present invention will be further described with reference to the drawings and examples, and the claims of the present invention are not limited to the examples.

Cylindrical member shown in Fig. 1 Strong rotation press deformation region strain rate
The strain rate range in the high temperature mechanical performance test is established based on the calculation formula. Rotating wheel forming angle α _ρ in rotating press forming, blank wall thickness t ₀ before rotating press, workpiece wall thickness t _f after rotating press, work from different θ layer between outer surface of blank before rotating press and outer surface of workpiece after rotating press. distance t _.theta.f leading to piece inner _surface, based wall partiality rate phi _t, the feed rate v _0, the relationship between them feeding speed v ₀ and the feed ratio f and spindle rotation n v is _{0 =} f · n, the tubular member Strong rotation press deformation area strain rate
Is determined within the range of 0.01/s to 10/s, and is usually within the range of 0.05/s to 5/s. Therefore, the strain rate of the high temperature mechanical performance test can be selected in the range of 0.01/s to 10/s.

The present invention uses hot work drawings based on dynamic material models. An external force is a work amount P corresponding to a unit volume material in a unit time in a material processing process, that is, a total energy obtained from the material. Based on the relationship between the work (energy) of the external force and the energy consumed by the plastic deformation of the material according to the hot working diagram of the dynamic material model, it becomes as shown in FIG. The total energy P obtained from the material is the stress σ and the strain rate.
It can be expressed by the product of, namely, the energy loss amount G consumed by plastic deformation and the energy supplemental loss amount J consumed by microstructural change. Among them, the distribution of the loss amount G and the supplementary loss amount J is determined by the strain velocity sensitivity coefficient m as shown in FIG.

As shown in FIG. 4A, when the material is in an ideal linear energy loss state, the strain rate sensitivity coefficient m=1, and the supplementary loss amount at this time is the maximum value J _max =P/2. Become. Generally, as shown in FIG. 4( b ), the material is in a non-linear energy loss state, and therefore, the microstructural change in the thermoplastic molding process using the power loss rate coefficient η as shown in FIG. Explain the ratio of energy loss in.

In the thermoplastic forming process, the deformation instability phenomenon of the material mainly includes the following local plastic flow, adiabatic shear band formation, void generation around a hard point, and grain boundary wedge type cleavage. In the hot working diagram based on the dynamic material model, it is judged by using the criterion of unstable current flow based on the maximum value principle of large plastic deformation irreversible thermal characteristics as shown in FIG. As shown in FIG. 6, the strain rate sensitivity coefficient m and the strain rate
If the stability criterion including
It means that there is an unstable danger under the condition of.

The flowchart of the hot-working tubular member hot-rotation shape/characteristic integrated control method of the present invention is as shown in FIG.

(Example 1)
The material is a brand Haynes 230 nickel-based high temperature alloy, which is a Ni-Cr-W-Mo solid solution strengthened low layer defect high temperature alloy. Among them, the cavity diameter d=54 mm, the wall thickness δ=2 mm, and the length l=500 mm of the tubular member (shown in FIG. 8) obtained by the strong hot rolling were used.

1. In this example, a high temperature plane strain compression test is used to perform a high temperature mechanical performance test. The sample is processed into a rectangular parallelepiped sample of 10×15×20 mm ³ as shown in FIG. 9 by adopting the wire cut system, and the loading system in the test process is as shown in FIG.

2. Based on literature and tests, it was determined that the Haynes 230 nickel-based high temperature alloy was about 1000° C., and therefore the temperature of the high temperature mechanical performance was determined to be 950° C. to 1200° C., one for each 50° C. Select a level and select a total of 6 levels. As shown in FIG. 1, the tubular member strong rotary press deformation region strain rate
Since the calculation formula of is obtained in the strain rate within the range of 0.01/s to 10/s, the strain rate of the test is 0.01/s, 0.1/s, 1/s, 10/s. Design on four levels.

3. The test adopts the design method of single element test, and a total of 24 sets of tests are conducted on the Gleeble-3500 thermal simulation tester. In the test process, the temperature of the sample is 50° C. which is necessary for the test at 10° C./s. The sample is heated to the above temperature for 3 minutes to evenly heat it, and then the temperature is lowered to the test temperature at 5°C/s for 5 minutes and then flat strain hot compression is performed. Is controlled to ensure isothermal compression, and after the actual strain amount is compressed to 1, the sample is quenched with a water-cooled method to retain the deformed structure as much as possible and to study the microstructure of the sample. To do. The heat load curve is as shown in FIG.

4. A high temperature plane strain compression test is performed according to the test method. The actual strain ε in the compression process is obtained by the natural logarithm of the ratio of the thickness h of the sample before and after compression and h-Δh, and the actual stress σ is the anvil load force. It is the ratio of the product of F and the anvil width w times the length b of the sample, that is, the ratio of the load force F and the contact area w·b between the anvil and the sample. The calculation formula is as shown in FIG. The strain coefficient A and the stress coefficient B are 0.866. The relationship of the obtained current flow stress strain is as shown in FIG.

5. Interpolate the test data and extend the finite set of 24 test conditions to the two-dimensional plane of temperature and strain rate with reasonable accuracy. Deformation temperature T and strain rate of power loss factor η obtained by the formula shown in FIG.
It is possible to calculate the distribution in the two-dimensional plane constituted by and to express it by isolines, that is, to obtain the power loss diagram under constant distortion as shown in FIG. The distribution of the temperature and strain rate in the two-dimensional plane of the value of the current instability determination criterion is calculated by the equation shown in FIG. 6 to obtain the current instability diagram under constant strain shown in FIG. 14 and FIG. 15 together, when the region that satisfies the criterion of instability of current flow as shown in FIG. 6 is shown in gray, the hot working diagram at the time of strain of the Haynes 230 alloy as shown in FIG. 16 is simple and intuitive. Obtained. The gray region in the figure is a region of unstable flow, that is, a dangerous region for plastic forming. A region in which the power loss rate coefficient η value is relatively large is a safety region advantageous for thermoplastic molding.

6. Based on the above step 5, the hot working diagram (shown in FIG. 17) at the maximum strain (strain ε=1) in the mechanical performance test of the present example was obtained, and the sample in the unstable region of the current transformation was obtained. The cause of the current instability can be determined by observing the metallographic texture for the. The plastic forming risk area of the obtained Haynes 230 nickel-based high temperature alloy is
>0.03, T<1025°C
>0.4, 1050° C.<T<1200° C., and the safety region advantageous for plastic forming is
<0.295, T>1050°C.

7. Perform hot strong rotation forming on the basis of the safety region that is determined by the hot working diagram and is advantageous for plastic forming. Since the Haynes 230 nickel-based high temperature alloy is manufactured by Haynes, Inc., USA, it is not possible to obtain a tubular member blank having a cavity diameter d=54 mm and a wall thickness Δ=5 mm as shown in FIG. A wire-cutting method is adopted to obtain a hot strong rotation blank, and the wall thickness is reduced from 5 mm to 2 mm in the rotary pressing process, and the thinning rate is 60%. The length of the tubular member blank is L=200 mm, that is, the length of the part is trimmed to 30 mm and the volume is not changed.
To confirm. We designed a rotating core mold with a diameter of 54 mm and a length of 600 mm, and attached it to the main shaft of a hot strong rotation vertical rotary press, using a cylindrical member blank with a specification of φ54*5 and length L=200 mm as the core mold. set. Three-rotation reverse rotation pitch rotary press molding (shown in FIG. 19) is adopted, and the axial pitch amount is a ₁₂ =a ₂₃ =2.5 mm.

8. The hot rolling temperature is 1100° C., the spindle rotation is 100 r/min, the rotary wheel forming angle is 20°, the feed ratio is 0.6 mm/r, and the thinning ratio is 26%. , 28%, 25% three times of rotary press molding, and the cylindrical member strong rotary press deformation region strain rate shown in FIG.
From the calculation formula, it can be seen that the strain rate is 0.13/s-0.165/s, which is within the safe region of Haynes 230 nickel base high temperature alloy plastic forming. High efficiency and energy saving electromagnetic induction heating is adopted in the rotary press process, and real-time feedback control is performed through the infrared thermometer and the temperature control system, and the rotary press area blank temperature is 1075 to 1125 ℃. Guarantee.

9. As an index for evaluating the dimensional accuracy after rotary press molding, the wall thickness deviation Ψ _t of the rotary press member, the straightness e _straightness , and the ellipticity e _ellipse are measured. Among them, the wall thickness deviation Ψ _t is the difference between the maximum value and the minimum value of the wall thickness in the rotary pressing stage in which the tubular member is stable. Straightness e _straight is the distance located between any prime line is the smallest two parallel planes within a fixed length of can measure the tubular member. The ellipticity e _ellipse is the difference between the maximum value and the minimum value of the outer diameter of the cross-section during the rotary pressing step in which the tubular member is stable. Wall thickness deviation [psi _t of the measured rotary press member is 0.107 mm, straightness e _straight is 0.17 mm, ellipticity e _oval is 0.20 mm, the component requirements are met.

10. As an index for evaluating the microstructure performance of the rotary press member after rotary press molding, metallographic structure observation, mechanical performance detection and micro hardness measurement are performed. The rotary press member was cut at a stable rotation stage (15 mm from the mouth) and tested, and HCl was used after insertion, polishing, and polishing, and HNO ₃ was etched with a 3:1 solution for 3 minutes. By observing the metallographic structure with an optical microscope, a fine and uniform complete recrystallized structure was obtained as shown in FIG. 20, and the average crystal grain size was changed from 19.2 μm before rotary pressing to 4.23 μm. Be miniaturized. Micro hardness measurement was performed with a HVS-1000Z type micro hardness meter using the sample after the observation of the metallographic structure, the average hardness of the blank before rotation was 191.14 HV, and the average hardness after rotary pressing increased to 315.74 HV. did. A uniaxial tensile mechanical performance test is performed on the rotary press member, and the yield strength thereof is increased from 480 MPa in the blank to 1110 MPa, and the tensile strength is basically unchanged and is maintained at about 1200 MPa.

From this, the Haynes 230 nickel-based alloy tubular member having good dimensional accuracy and excellent texture was obtained by the method for controlling the hot-rolling shape/property integration of the tubular member based on the hot work drawing of the present invention. You can see that.

(Example 2)
The material is 304 stainless steel, which is the most common Cr-Ni stainless steel. Among them, the cavity diameter d of the tubular member (shown in FIG. 8) obtained by strong hot rotation was 50 mm, the wall thickness was δ=2 mm, and the length was 1=500 mm.

1. In this example, a high temperature uniaxial tensile test is used to perform a high temperature mechanical performance test. The sample is processed into a high temperature uniaxial tensile sample as shown in FIG. 21 by adopting the wire cut method.

2. By combining literature and tests, it was confirmed that the dynamic recrystallization temperature of 304 stainless steel was about 950°C, and therefore the temperature of high temperature mechanical performance was confirmed to be 900°C-1100°C, and 50°C. Choose one level for each, for a total of five levels. Similarly, the strain rate of the test is designed at four levels of 0.01/s, 0.1/s, 1/s, and 10/s.

3. The test adopts the design method of the single element test, 20 sets of tests are conducted in the Gleeble-3500 thermal simulation tester, the resistance heating method is adopted in the test process, and the heat load curve is as shown in FIG. First, at 10° C./s, the tensile deformation portion was heated to a temperature required for the test of 50° C. or higher, and was kept warm for 3 minutes to uniformly heat the sample. Further, the temperature was lowered to 5° C./s to the test temperature and kept for 5 minutes. Then, after the sample breaks, the uniaxial tensile test is continued until the sample is quenched by water cooling.

4. Interpolate the test data and extend the finite 20 sets of test conditions to a two-dimensional plane with reasonable accuracy of temperature and strain rate. The power loss rate coefficient η obtained by calculation based on the formula shown in FIG. 5 is expressed by contour lines to obtain a power loss diagram under constant distortion as shown in FIG. The distribution of instability determination criteria for temperature and strain rate is calculated in the two-dimensional plane by the equation shown in FIG. 6, and a current instability diagram under constant strain as shown in FIG. 15 is acquired. .. If the region satisfying the current flow instability judgment criteria shown in FIG. 6 is shown in gray together with the power loss diagram and the current flow instability diagram, a hot working diagram as shown in FIG. 16 can be obtained easily and intuitively. .. The gray region in the figure is a region of unstable flow, that is, a dangerous region for plastic forming. A region in which the power loss rate coefficient η value is relatively large is a safety region advantageous for thermoplastic molding. To obtain the 304 stainless steel plastic forming risk area, 0.1<
<1, 900°C <T <1000°C
>1, 1000°C<T<1100°C, and the safety region for plastic molding is
<0.5, 1000° C. <T<1100° C.

5. Hot strong rotation forming is performed based on the safety region that is advantageous for plastic forming determined by the hot working diagram. Since 304 stainless steel raw pipe with cavity diameter d=50 mm and wall thickness Δ=5 mm can be purchased in the market, directly purchase the raw pipe of related dimensions and perform hot strong rotation forming. The length of the tubular member blank is L=200 mm, that is, the length of the part is trimmed to 30 mm, and the volume does not change.
To confirm. We designed a rotating core mold with a diameter of 50 mm and a length of 600 mm, and attached it to the main shaft of a vertical hot strong rotation press machine. The cylindrical member blank with a specification of φ50*5 and length L=200 mm was used as the core mold. set. Three-rotation reverse rotation pitch rotary press molding (shown in FIG. 19) is adopted, and the axial pitch amount is a ₁₂ =a ₂₃ =2.5 mm.

6. The wall thickness of the blank was thinned from 5 mm to 2 mm during the high-speed hot-rolling, and the thinning rate was 60%. The hot strong rotation temperature is 1050° C., the spindle rotation is 100 r/min, the rotary wheel forming angle is 20°, the feed ratio is 0.4 mm/r, and the thinning ratios are 26% and 28, respectively. %, 25% three times of rotary press molding, the tubular member strong rotary press deformation region strain rate shown in FIG.
From the calculation formula, it is found that the strain rate is 0.088/s-0.11/s, which is within the safe region of 304 stainless steel plastic forming. High efficiency and energy saving electromagnetic induction heating is adopted in the rotary press process, and real-time feedback control is performed through the infrared thermometer and the temperature control system, and the rotary press area blank temperature is 1025°C to 1075°C. Guarantee.

7. The wall thickness deviation Ψ _t of the rotary press member, the straightness e _straightness , and the ellipticity e _ellipse are measured as indexes for evaluating the dimensional accuracy after rotary press molding. Wall thickness deviation [psi _t of the measured rotary press member is 0.102 mm, straightness e _straight is 0.11 mm, ellipticity e _oval is 0.13 mm, the component requirements are met.

8. As an index for evaluating the structure performance of the rotary press member after the rotary press molding, the metallographic structure observation and mechanical performance detection are performed. The rotary press member was cut at a stable rotation stage (15 mm from the mouth) and tested, and HCl was used after insertion, polishing, and polishing, and HNO ₃ was etched with a 3:1 solution for 3 minutes. By observing the metallographic structure with an optical microscope, a fine, uniform and uniform fibrous structure can be obtained. The average crystal grain size is reduced from 13.03 μm before rotary pressing to 2.26 μm. A uniaxial tensile mechanical performance test was performed on the rotary press member, and the yield strength was increased from 269 MPa to 560 MPa in the blank state, the tensile strength was increased from 705 MPa to 846 MPa, and the elongation rate was maintained at about 40%. ..

From this, the Haynes 230 nickel-based alloy tubular member having good dimensional accuracy and excellent texture was obtained by the method for controlling the hot-rolling shape/property integration of the tubular member based on the hot work drawing of the present invention. You can see that.

As described above, the present invention can be preferably implemented.

The embodiments of the present invention are not limited to the above-described examples, and various changes, modifications, substitutions, combinations, and simplifications are equivalent to the replacement without departing from the scope of the present invention. It is included in the protection scope of.

(Appendix)
(Appendix 1)
High temperature mechanical performance of metal materials under the temperature, strain rate and strain condition of dynamic recrystallization based on the difference of temperature, strain rate and strain of dynamic recrystallization in thermoplastic forming process of different metal materials A step (1) of conducting a test,
A step (2) of performing an interpolation calculation on the relation between the flow stress and the strain obtained under the limited test temperature and strain rate sample points;
Based on the criteria of power loss and current instability in the thermoplastic forming process, the relationship between current stress and strain was obtained in the extended thermodynamic performance test based on the criteria of power loss and current instability at different strains. Step (3) of constructing the diagram,
A hot working diagram of the material is obtained by combining the power loss diagram and the current instability diagram, and based on the distribution of the power loss factor η and the current instability judgment, the potential risk of the current instability criterion is A step (4) of analyzing and obtaining a molding condition advantageous for thermoplastic molding having a power loss rate coefficient η under the condition that the molding condition and the safe molding condition are satisfied;
Finally, the material obtained according to the hot working diagram is advantageous for the temperature and strain rate of hot forming, and the hot strong rotational forming process parameters are established, and the tubular member is subjected to hot strong rotational forming to obtain the dimensional accuracy. And a step (5) of obtaining a tubular member satisfying the requirements of the tissue performance,
A method for controlling hot shape/characteristic integration of a cylindrical member on the basis of a hot working drawing, including:

(Appendix 2)
The metal material of step (1) is a metal or an alloy having a middle-to-low layer defect in which dynamic recrystallization is likely to occur in the thermoplastic forming process, and the high temperature mechanical performance test temperature of step (1) is the dynamic recrystallization of the material. A method for controlling hot-rotation shape/characteristic integration of a tubular member based on the hot working diagram described in appendix 1, characterized in that the temperature is within a range of 50° C. or lower of the crystallization temperature and 50° C. or higher of the thermoplastic molding temperature. ..

(Appendix 3)
The hot-working drawing of step (5) is a hot-working drawing based on a dynamic material model. Integrated control method.

(Appendix 4)
The strain rate of the high temperature mechanical performance test of step (1) is in the range of 0.01/s to 10/s according to the distribution of the high-speed rotary press strain rate of the tubular member, and the high temperature mechanical performance of step (1) is The test guarantees that the amount of strain is 0.6 or more. The method for controlling the hot-rotation shape/characteristic integration of a tubular member based on the hot-working drawing described in Appendix 1.

(Appendix 5)
The step (2) of the interpolation calculation expands the number of temperature and strain rate test samples. Control method.

(Appendix 6)
In step (3), the strain rate sensitivity coefficient m on the basis of the instability of the current transformation is the strain rate of the current stress σ.
Is a partial differential with respect to, and determines the distribution of energy G lost due to plastic deformation and energy J lost due to microstructural change,
The amount of work that the external force exerts on the unit volume material in a unit time in the material processing process is P, that is, the total energy obtained by the material is the stress σ and the strain rate.
The energy G consumed by the plastic deformation of the material and the energy J consumed by the microstructural change obtained by multiplying by
Is converted to
The ideal energy loss system is considered to be equal to the energy consumed by plastic deformation and microstructural change, but usually the material is in a non-linear energy loss state, and the Strain rate of stress σ
The partial differential with respect to is adopted, that is, the strain rate sensitivity coefficient m
Explains its distribution ratio,
A method of controlling hot shape/characteristic integration of a tubular member on the basis of the hot working drawing described in Appendix 1.

(Appendix 7)
The dangerous forming condition of the step (4) is a condition satisfying the current instability criterion based on the irreversible thermodynamic extreme value principle of large plastic deformation explained by the strain rate sensitivity coefficient m,
Based on the irreversible thermodynamic extremum principle of large plastic deformation, the current instability criterion is calculated using the strain rate sensitivity coefficient m and the function of strain rate.
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An advantageous condition for thermoplastic forming is a large forming condition that explains the power loss rate coefficient η occupied by the energy J lost due to the change in microstructure, and when placed in an ideal linear energy loss system, The _maximum energy lost is J _max =P/2, and therefore the power loss rate η is explained using the function of the strain rate sensitivity coefficient m based on the relationship between the total energy P obtained from the material and the loss energy. Therefore, the ratio of energy J lost from the microstructure
To explain,
A method of controlling hot shape/characteristic integration of a tubular member on the basis of the hot working drawing described in Appendix 1.

(Appendix 8)
The hot strong rotational molding temperature of step (5) needs to be controlled within a range of ±25° C., which is advantageous to the thermoplastic molding temperature obtained in the hot molding diagram, and the additional heat treatment is performed. A method for controlling the shape/characteristic integration of the hot rolling of a cylindrical member based on a hot working drawing.

(Appendix 9)
The hot strong rotational forming strain rate in the step (5) is realized by controlling the rotating wheel forming angle, the rotating wheel feed ratio, the spindle rotation, the thinning rate and/or the blank wall thickness,
Determining the hot strong rotary molding parameters is the strain rate of the strong rotary press deformation region of the tubular member.
And the rotary wheel forming angle α _ρ , the blank wall thickness t ₀ before the rotary press, the wall thickness t _f of the workpiece after the rotary press, the wall thickness thinning ratio φ _t , and the feed speed v ₀ .
Where α _ρ is the rotary wheel forming angle, t ₀ is the blank wall thickness before the rotary press, t _f is the workpiece wall thickness after the rotary press, and t _θf is the rotary press. The distance from the different θ layers between the outer surface of the front blank and the outer surface of the workpiece after rotary pressing to the inner surface of the workpiece, φ _t is the wall thinning ratio, and v ₀ is the flow velocity of the molding region mass point in front of the rotating wheel (rotation). (In relation to the wheel), in reverse rotational molding, v ₀ is equal to the feed rate, and the relationship between the feed ratio f and the spindle rotation n is v ₀ =f·n.
A method of controlling hot shape/characteristic integration of a tubular member on the basis of the hot working drawing described in Appendix 1.

(Appendix 10)
The dynamic recrystallization condition of step (1) is that the stress in the grain boundary and the stress of high dislocation density is caused by the dislocation density reaching a critical value in the thermoplastic forming process in the middle-low layer defect metal material of step (1). Appendix 1 characterized in that such a microstructural change process is called dynamic recrystallization in order to form recrystallization nuclei having extremely low dislocation density at a concentrated portion and to grow easily and to distinguish recrystallization in the heat treatment process. A method for controlling the shape/characteristic integration of the hot rolling of a cylindrical member based on the hot working diagram described in.

Claims (10)

High temperature mechanical performance of metal materials under the temperature, strain rate and strain condition of dynamic recrystallization based on the difference of temperature, strain rate and strain of dynamic recrystallization in thermoplastic forming process of different metal materials A step (1) of conducting a test,
A step (2) of performing an interpolation calculation on the relation between the flow stress and the strain obtained under the limited test temperature and strain rate sample points;
Based on the criteria of power loss and current instability in the thermoplastic forming process, the relationship between current stress and strain was obtained in the extended thermodynamic performance test based on the criteria of power loss and current instability at different strains. Step (3) of constructing the diagram,
A hot working diagram of the material is obtained by combining the power loss diagram and the current instability diagram, and based on the distribution of the power loss factor η and the current instability judgment, the potential risk of the current instability criterion is A step (4) of analyzing and acquiring a molding condition advantageous for thermoplastic molding having a power loss rate coefficient η under the condition that the molding condition and the safe molding condition are satisfied;
Finally, the material obtained according to the hot working diagram is advantageous for the temperature and strain rate of hot forming, and the hot strong rotational forming process parameters are established, and the tubular member is subjected to hot strong rotational forming to obtain the dimensional accuracy. And a step (5) of obtaining a tubular member satisfying the requirements of the tissue performance,
A method for controlling hot shape/characteristic integration of a cylindrical member on the basis of a hot working drawing, including: The metal material of step (1) is a metal or an alloy having a medium-to-low layer defect in which dynamic recrystallization is likely to occur in the thermoplastic forming process, and the high temperature mechanical performance test temperature of step (1) is the dynamic recrystallization of the material. 2. The control of the hot-rotating shape/characteristic integration of the tubular member based on the hot working diagram according to claim 1, wherein the temperature is within the range of 50° C. or lower of the crystallization temperature and 50° C. or higher of the thermoplastic molding temperature. Method. The hot-working shape of the tubular member based on the hot-working drawing according to claim 1, wherein the hot-working drawing of step (5) is a hot-working drawing based on a dynamic material model. Control method of characteristic integration. The strain rate of the high temperature mechanical performance test of step (1) is in the range of 0.01/s to 10/s according to the distribution of the high-speed rotary press strain rate of the tubular member, and the high temperature mechanical performance of step (1) is The method for controlling the hot-rotation shape/characteristic integration of a tubular member based on a hot-working drawing according to claim 1, wherein the test guarantees that the strain amount is 0.6 or more. The hot-rolling shape/characteristic integration of a tubular member according to claim 1, wherein the interpolation calculation in step (2) extends the number of temperature and strain rate test samples. Control method. In step (3), the strain rate sensitivity coefficient m on the basis of the instability of the current transformation is the strain rate of the current stress σ.
Is a partial differential with respect to, and determines the distribution of energy G lost due to plastic deformation and energy J lost due to microstructural change,
The amount of work that the external force exerts on the unit volume material in a unit time in the material processing process is P, that is, the total energy obtained by the material is the stress σ and the strain rate.
The energy G consumed by the plastic deformation of the material and the energy J consumed by the microstructural change obtained by multiplying by
Is converted to
The ideal energy loss system is considered to be equal to the energy consumed by plastic deformation and microstructural change, but usually the material is in a non-linear energy loss state, and the Strain rate of stress σ
A partial differential with respect to the strain rate sensitivity coefficient m
Explains its distribution ratio,
The method for controlling the hot-rotation shape/characteristic integration of a tubular member based on the hot-working drawing according to claim 1, characterized in that. The dangerous forming condition of the step (4) is a condition satisfying the current instability criterion based on the irreversible thermodynamic extreme value principle of large plastic deformation explained by the strain rate sensitivity coefficient m,
Based on the irreversible thermodynamic extremum principle of large plastic deformation, the current instability criterion is calculated using the strain rate sensitivity coefficient m and the function of strain rate.
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An advantageous condition for thermoplastic forming is a large forming condition that explains the power loss rate coefficient η occupied by the energy J lost due to the change in microstructure, and when placed in an ideal linear energy loss system, The _maximum energy lost is J _max =P/2, and therefore the power loss rate η is explained using the function of the strain rate sensitivity coefficient m based on the relationship between the total energy P obtained from the material and the loss energy. Therefore, the ratio of energy J lost from the microstructure
To explain,
The method for controlling the hot-rotation shape/characteristic integration of a tubular member based on the hot-working drawing according to claim 1, characterized in that. The hot hot rotomolding temperature of step (5) needs to be controlled within a range of ±25° C., which is advantageous to the thermoplastic molding temperature obtained from the hot forming diagram. Control method of hot-rotation shape/characteristic integration of a cylindrical member based on the hot-working diagram of FIG. The hot strong rotational forming strain rate in the step (5) is realized by controlling the rotating wheel forming angle, the rotating wheel feed ratio, the spindle rotation, the thinning rate and/or the blank wall thickness,
Determining the hot strong rotary molding parameters is the strain rate of the strong rotary press deformation region of the tubular member
And the rotary wheel forming angle α _ρ , the blank wall thickness t ₀ before the rotary press, the wall thickness t _f of the workpiece after the rotary press, the wall thickness thinning ratio φ _t , and the feed speed v ₀ .
Where α _ρ is the rotary wheel forming angle, t ₀ is the blank wall thickness before the rotary press, t _f is the workpiece wall thickness after the rotary press, and t _θf is the rotary press. The distance from the different θ layers between the outer surface of the front blank and the outer surface of the workpiece after rotary pressing to the inner surface of the workpiece, φ _t is the wall thinning ratio, and v ₀ is the flow velocity of the molding region mass point in front of the rotating wheel (rotation). (In relation to the wheel), in reverse rotational molding, v ₀ is equal to the feed rate, and the relationship between the feed ratio f and the spindle rotation n is v ₀ =f·n.
The method for controlling the hot-rotation shape/characteristic integration of a tubular member based on the hot-working drawing according to claim 1, characterized in that. The dynamic recrystallization condition of step (1) is that the stress in the grain boundary and the high dislocation density is caused by the dislocation density reaching a critical value in the thermoplastic molding process in the middle-low layer defect metal material of step (1). A recrystallization nucleus having a very low dislocation density is formed at a concentrated portion and is easily grown, and in order to distinguish recrystallization in a heat treatment process, such a microstructural change process is called dynamic recrystallization. A method for controlling the shape/characteristic integration of a hot-rotating cylindrical member based on the hot-working drawing described in 1.